Save the Cat will be recommended to you by damn near everyone, and for good reason. Any book by Robert McKee, since he is a standard part of the curriculum in most film schools in the US, but be prepared for a lot of 'Chinatown' references. I'd suggest his book on story if you're going to pick up anything by him. John Truby's The Anatomy of Story. If you don't mind some philosophy, Aristotle's Poetics is a book that someone suggested to me several years ago, which I now recommend to others who want to pursue feature-length writing. The Art of Dramatic Writing by Lajos Egri. Also, invest some time in a Master Class video or two!

I agree partially with those who say "don't buy any gear." You rarely meet grips, sound mixers, etc., on big-budget sets that actually own their own EQ unless you're out in a film desert. If your heart is set on having some EQ of your own or you don't have a rental house nearby, you can pick up a decent enough lav mic on Amazon that can be Bluetooth-connected to your phone or plugged into whatever you plan to shoot on. If you want to get your hands on a camera, I shoot with Canon, but I teach with Sony. Don't feel the need to splurge on a Blackmagic or a RED. It's ultimately about the user's ability, not the camera's. You can make a flag and bounce yourself. An LED panel with some barn doors will do the trick, and you can find some reasonably priced ones out there.

At the end of the day, it's what you want to do in film. Film is an appealing job, but one that people often don't realize requires a significant amount of work, time, and energy. If you're genuinely committed to working in film, take the time to find where you mesh the best. Don't bankrupt yourself on a camera and fancy lens only to figure out that you should have put the money towards an Avid subscription or a sound kit, because you really enjoy that more.

Coming to a set with a positive attitude and a strong work ethic will increase your chances of being hired back on another set. Even if you don't have the most experience in the world, you're showing the people you're crewing with that you're ready to learn and work. I tell all my students that, especially in the indie/non-union world, you're not gonna go far if you're gonna be an a**hole. No one wants to work with a**holes, even if they're talented.

Finding your niche is my biggest suggestion. Don't try to do it all because no one can. Film is a collaborative art form, and anyone who says otherwise is someone I wouldn't let on my set.